1. Field of the Invention
The present invention relates to a hard disk drive. More particularly, the present invention relates to a data storage hard disk and a spindle motor assembly for rotating a hard disk.
2. Description of the Related Art
A hard disk drive (HDD) is a device that stores and reproduces data on a data storage disk using a read/write head. The data storage hard disk is mounted on and rotated by a spindle motor, and to read/write data, the read/write head is moved by an actuator to the desired position above the recording surface of the rotating hard disk.
FIG. 1 is an exploded perspective view of a spindle motor assembly of a hard disk drive of the prior art, and FIG. 2 is a side view of the spindle motor assembly shown in FIG. 1. Referring to FIGS. 1 and 2, the spindle motor assembly of the prior art includes a data storage hard disk 20, a spindle motor 30 for rotating the data storage hard disk 20, a disk clamp 40, and a clamping screw 50. The spindle motor 30 is installed on a base of the hard disk drive and includes a shaft 32 and a hub 34 rotating about the shaft 32. The hard disk 20 has a hole 21 at its center and into which the hub 34 can be inserted, thereby allowing the hard disk 20 to be mounted on the hub 34 and rotated therewith. The disk clamp 40 is mounted on the spindle motor 30 to securely fix the hard disk 20 to the spindle motor 30. Specifically, the disk clamp 40 is fixed to the spindle motor 30 by the clamping screw 50. To this end, the disk clamp 40 has at its center a countersunk hole 41 into which the clamping screw 50 is inserted, and the shaft 32 of the spindle motor 30 has a threaded fastening hole 35. The clamping screw 50 is threaded into the screw fastening hole 35. Thus, the disk clamp 40 is resiliently deformed by the clamping screw 50, thereby pressing the disk 20 against and securely fixing the disk 20 to the hub 34 of the spindle motor 30.
As described above, in the prior art spindle motor assembly, the hard disk 20 needs the hole 21 at its center in order for the hard disk 20 to be mounted on the hub 34 of the spindle motor 30. However, the process for forming the hole 21 at the center of the hard disk 20 is not easy, and adds to the cost of manufacturing the spindle assembly and hence, the hard drive. In particular, the hard disk 20 is likely to be damaged when it is machined, i.e., when the hole 21 is formed, because the hard disk 20 is typically made of glass.
Also, in the conventional spindle motor assembly, the disk clamp 40 contacts the surface of the hard disk 20 to fix the hard disk to the spindle motor 30. The hard disk 20 may be warped because the force exerted by the disk clamp 40 on the hard disk 20 is not uniform in the circumferential direction of the hard disk.
Furthermore, in the conventional spindle motor assembly, the hard disk 20 and the disk clamp 40 are discrete members. Therefore, the hard disk 20 can slip to an eccentric position when shocks or vibration are applied to the spindle motor assembly while or after the hard disk 20 is assembled onto the spindle motor 30.
Finally, hard disk drives are increasingly being used in mobile electronics. Therefore, there is an increasing demand for miniaturized hard drives. The spindle motor assembly of the conventional motor spindle assembly shown in FIG. 2 having a 0.85 inch hard disk has an overall height H of about 4.11 mm. However, it is very difficult to miniaturize this spindle assembly, especially to reduce the height of the assembly, because of the disk clamp 40.